Clostridium difficile is a gram-positive anaerobic bacterium whose clinical manifestations include diarrhea, pseudomembraneous colitis, sepsis, and death. Progression from colonization to infection and recrudescent disease reflects a failure to mount an effective antibody response against the toxins released by the bacterium.
Common treatments for C. difficile-associated diseases include terminating the original antibiotic treatment and administering either metronidazole or vancomycin. Both metronidazole and vancomycin, however, have particular disadvantages. Vancomycin, the only therapy approved by the United States Food and Drug Administration, (USFDA) is associated with selection of resistant gram positive pathogens, while metronidazole appears less effective than vancomycin for severe C. difficile disease. Both agents do not prevent relapse of C. difficile infection after termination of treatment, a situation also associated with poor anti-toxin immune responses and one that can be very difficult to treat.
Therefore, there is a need for new, more effective approaches to treating and preventing C. difficile-associated diseases.